This R21 application relates to the Mechanisms of Alcohol-Induced Tissue Injury program announcement. Fetal alcohol spectrum disorders (FASD) are the leading known cause of birth defects and mental impairment in the United States. The mechanisms of alcohol- induced damage to developing neurons are not completely understood. This study proposes a new alternative to unravel biochemical pathways that participate in the onset of FASD and discover candidate clinical biomarkers for better diagnosis and management of this disorder. Metabolomics of human embryonic (hES) stem cells, neural precursors and neurons will identify and measure which metabolites and pathways are significantly altered by alcohol injury. These metabolites, which cross the blood-brain barrier and fetal-maternal interface, serve as candidate biomarkers for early diagnosis of FASD. Next, the study will examine the effects of alcohol on cell viability and functional aspects of human neurogenesis with particular emphasis on serotonergic (5HT) neurons. Serotonergic neurons are an important but relatively unexplored candidate for alcohol injury in the developing human brain;these neurons are more susceptible to the effects of the environment than other subtypes. 5HT neurons play a central role in cognitive disorders that are common to children with FASD, such as deficits in learning, memory, executive functioning, motor skills, judgment and attention-deficit hyperactivity disorders. Our future goal is to examine if candidate biomarkers detected here are also altered in the blood (serum) of infants affected by FASD versus healthy individuals. Most importantly, the candidate clinical biomarkers discovered in this study may be contribute to prevention of FASD since they could be used in prenatal screening to identify pregnant women at risk and their affected offspring.